The association of tendinous xanthomata (including Achilles tendon xanthomas) with familial hypercholesterolemia (FH) has been well recognized ¹. In FH there is a reduction in functionally active LDL receptors, thus its metabolism and excretion, resulting in abnormal deposition of cholesterol in soft tissues and blood vessels ¹.

Deposition of lipid-laden macrophages (foam cells) in tendons results in the formation of tendinous xanthomata. They are commonly seen in Achilles tendons, extensor tendons of hands and feet, and in triceps tendons ^1,3. Studies have shown that cholesterol-lowering statins can also lessen the size of tendinous xanthomas. These lesions are usually bilateral and painless ¹, but can sometimes be painful and itchy.

Radiography of ankles reveals bilateral well defined non-calcified soft tissue swelling, without osseous or joint abnormalities.

Ultrasonography using a high-resolution linear-array probe shows marked nodular enlargement and mixed echotexture of affected tendons with hypoechoic nodules representing xanthoma ⁵.

Fusiform enlargement of affected tendons with vertical striations of high and low signal can be seen in T1W and T2W MR Images. MRI features of tendon xanthomata, although characteristic diagnostic overlap occurs with partial tendon tears and tendinopathies ². MRI imaging features can be seen even before clinically detectable tendon enlargement ³.

Our patient shows the classical radiological imaging characteristics of tendinous xanthomata of Achilles and tibialis posterior tendons.